Polariscope Guide, Part 1: Testing Gemstone Refraction
The polariscope is one of gemology’s simplest and most useful tools. With a little practice and our three-part polariscope guide, you’ll…
Ultraviolet Testing and Gemstone Identification
Gemstone identification typically starts with measuring a specimen’s refractive index (RI) and specific gravity (SG). These two tests…
Gemstone Magnetism: The Forgotten Property
Although gemstone magnetism isn’t a commonly tested gemstone property, it may be useful for making quick separations outside the lab. By Richard…
Gemstone Optical Properties
We tend to take light for granted. It’s such a common thing we experience every day. Rarely do we think of the scientific definition of light…
Gemstone Physical Properties
Step 2: Advanced Gemology Lesson 2 Back to syllabus The optical properties of gems attract our eyes and can give a cut stone a unique character. However,…
A Beginner’s Guide To Common Gemstone Heat Treatments
Gemstone heat treatments can turn mediocre pieces into items of great beauty. Heating a gem to a specific temperature and then cooling it is a common…
Identifying Inclusions Found in Enhanced Gems
Gemstone treatments can have a significant impact on the value and stability of a stone. The following enhancement processes leave behind some…
Identifying Inclusions of Specific Gems
Imagine you find this blue gemstone for sale at a pawn shop. Can the inclusions you see help you narrow the range of possible identifications? Absolutely.…
A Guide to Gem Cutting Styles
While some cut names may describe the face-up shape of the finished gem, others refer to the shape and arrangement of the gem’s facets. These cuts…
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